A FEN describes a chess position in one line. Paste it into the field below and the position opens on the board in analysis mode: Stockfish 18 shows the evaluation, the best move and the engine lines. From there you can play moves for either side and the engine evaluates each new position.
How to open a position from a FEN
- Copy the FEN. On Lichess it is under the board in analysis mode. On Chess.com, click Share on the game page and open the PGN tab; the FEN is above the PGN text.
- Paste it into the field above. A Lichess analysis-board link that carries the position works too.
- Read the evaluation and the lines. The same position also opens from a direct link like /position?fen=....
FEN format explained
A FEN string has six fields separated by spaces:
- Piece placement. Ranks 8 to 1, separated by slashes. Uppercase letters are White’s pieces, lowercase are Black’s, and a digit counts empty squares in a row.
- Active color: w for White to move, b for Black.
- Castling rights. KQkq lists what is still available; a dash means none.
- En passant square, or a dash if there is none.
- Halfmove clock: moves since the last pawn move or capture, for the 50-move rule.
- Fullmove number in the game.
Related tools
- Online Chess Board: set up a position by hand, without a FEN.
- PGN Analyzer: a whole game from a PGN.
- Chess Analyzer: how to read the evaluation and engine lines.
FAQ
What is FEN in chess?
FEN is a text format that describes a chess position in full: the pieces, the side to move, castling rights, the en passant square and the move counters.
How do I copy FEN from Chess.com or Lichess?
On Lichess, the FEN is under the board in analysis mode. On Chess.com, click Share on the game page and open the PGN tab: the FEN is above the PGN text.
Can I open a FEN with a URL parameter?
Yes: /position? fen=<FEN> opens that position straight in analysis mode.
What if I only have the piece placement?
Paste it into the field and the rest is filled in: White to move, no castling. If that is wrong, fix the position in the editor.
Which engine evaluates the position?
Stockfish 18 in your browser, at depth 15 for free and up to 22 with Pro. If the position is already in our evaluation database, the lines come from there.
Is there an API for FEN evaluations?
No. The link opens the position in a browser and the evaluation is computed on the page; chess.rodeo has no public evaluation API.